Reply by Loren

An easy way to do it is make the frames with no profilesusing loose tenons or bridle joints or whatever you prefer,then rout a rabbet in the back of the frame. You can put the panel in from behind and use applied mouldingsto cover the gap. I do this from the front too, withwainscott style mouldings.

Another way to do it is with mitered door frame corners. In this case the grooves don’t interfere with loose tenonjoints.